I think the OP indirectly does that. They chose to say

“The median age of female's first marriage was less than 22 for 100 years and rose to 28 in the last few decades”

and not

“The median age of male's first marriage was less than 26 for 100 years and rose to 30 in the last few decades”

or the neutral

“The median age of first marriage was more or less stable for 100 years and rose by about 6 years in the last few decades”